Complementary metal oxide semiconductor device with III-V optical interconnect having III-V epitaxial semiconductor material formed using lateral overgrowth

ABSTRACT

An electrical device that includes a first semiconductor device positioned on a first portion of a substrate and a second semiconductor device positioned on a third portion of the substrate, wherein the first and third portions of the substrate are separated by a second portion of the substrate. An interlevel dielectric layer is present on the first, second and third portions of the substrate. The interlevel dielectric layer is present over the first and second semiconductor devices. An optical interconnect is positioned over the second portion of the semiconductor substrate. At least one material layer of the optical interconnect includes an epitaxial material that is in direct contact with a seed surface within the second portion of the substrate through a via extending through the least one interlevel dielectric layer.

BACKGROUND

Technical Field

The present disclosure relates to semiconductor devices, such asoptoelectronic devices composed of III-V semiconductor materials.

Description of the Related Art

The dimensions of semiconductor field effect transistors (FETs) havebeen steadily shrinking over the last thirty years or so, as scaling tosmaller dimensions leads to continuing device performance improvements.With increasing scaling of semiconductor devices, the interconnects havealso been decreasing in size. Typically, as the interconnect size hasdecreased, the resistance of the interconnects has increased. Withincreased scaling of semiconductor devices leading to increasedswitching speeds, the obstruction to further performance enhancements isthe speed at which data signals can be transmitted over interconnects.

SUMMARY

In one aspect, an electrical device is provided that includes a firstsemiconductor device positioned on a first portion of a semiconductor oninsulator (SOI) substrate, and a second semiconductor device positionedon a third portion of a SOI substrate. An optical interconnect ispositioned on a second portion of the SOI substrate that is presentbetween the first and third portions of the SOI substrate, wherein theoptical interconnect is formed on at least one interlevel dielectriclayer that is present over at least one of the first and secondsemiconductor devices. The optical interconnect includes a III-V lightemission device, a dielectric waveguide and a III-V light detectiondevice, wherein at least one material layer of at least one of the III-Vlight emission device and the III-V light detection device is anepitaxial material that is in direct contact with the base semiconductorsubstrate of the SOI substrate through a via extending through the leastone interlevel dielectric layer and a buried dielectric layer of the SOIsubstrate.

In another embodiment, an electrical device is provided that includes afirst semiconductor device positioned on a first portion of a substrate,and a second semiconductor device positioned on a third portion of thesubstrate. The first and third portions of the substrate are separatedby a second portion of the substrate. An interlevel dielectric layer ispresent on the first, second and third portions of the substrate,wherein the interlevel dielectric layer is present over the first andsecond semiconductor devices. An optical interconnect is positioned overthe second portion of the semiconductor substrate. At least one materiallayer of the optical interconnect is an epitaxial material that is indirect contact with a seed surface within the second portion of thesubstrate through a via extending through the least one interleveldielectric layer.

In another aspect, a method of forming an electrical device is providedthat includes forming a first semiconductor device on a first portion ofa substrate, and forming a second semiconductor device on a thirdportion of the substrate. The first and third portions of the substrateare separated by a second portion of the substrate. At least oneinterlevel dielectric layer is formed over the first, second and thirdportions of the substrate, wherein at least the first and secondsemiconductor devices are covered by the at least one interleveldielectric layer. At least one via is formed through the at least oneinterlevel dielectric to expose a seed substrate surface in the secondportion of the substrate. An optical interconnect is formed on a surfaceof the at least one interlevel dielectric layer overlying the secondportion of the substrate, wherein at least one material layer of theoptical interconnect is epitaxial grown from the seed substrate surfacethrough at least one via extending onto the upper surface of the atleast one interlevel dielectric layer.

BRIEF DESCRIPTION OF DRAWINGS

The following detailed description, given by way of example and notintended to limit the disclosure solely thereto, will best beappreciated in conjunction with the accompanying drawings, wherein likereference numerals denote like elements and parts, in which:

FIG. 1 is a side cross-sectional view depicting an electrical deviceincluding two semiconductor devices present on a semiconductor oninsulator (SOI) substrate, in which data transmission between the twosemiconductor devices includes an optical interconnect, in accordancewith one embodiment of the present disclosure

FIG. 2 is a side cross-sectional view depicting an electrical deviceincluding three semiconductor devices present on a bulk semiconductorsubstrate, in which data transmission between at least two of thesemiconductor devices includes an optical interconnect, in accordancewith another embodiment of the present disclosure.

FIG. 3 is a side cross-sectional view depicting one embodiment of datatransmission through the electrical device that is depicted in FIG. 1.

FIG. 4 is a side cross-sectional view depicting semiconductor devicesthat have been formed on a semiconductor on insulator (SOI) substratefollowing back end of the line (BEOL) processing, wherein vias have beenformed through the at least one interlevel dielectric layer to exposed aseed surface of the SOI substrate, in accordance with one embodiment ofthe present disclosure.

FIG. 5 is a side cross-sectional view depicting epitaxially forming aIII-V semiconductor material from the seed surface of SOI substrate,wherein the III-V semiconductor material fills the vias and provides atleast a base material layer for the optoelectronic light emission deviceand/or optoelectronic light detecting device of an optical interconnect,in accordance with one embodiment of the present disclosure.

FIG. 6 is a side cross-sectional view depicting forming anoptoelectronic light emission device comprising a type III-Vsemiconductor materials and the optoelectronic light detection devicecomprising III-V semiconductor materials on the epitaxially grown III-Vsemiconductor material layers depicted in FIG. 5, in accordance with oneembodiment of the present disclosure.

FIG. 7 is a side cross-sectional view depicting one embodiment offorming a dielectric waveguide, in accordance with the presentdisclosure.

FIG. 8. is a top down view illustrating the structure that is depictedin FIG. 7.

FIG. 9 is a side cross-sectional view depicting semiconductor devicesthat have been formed on a bulk semiconductor substrate following backend of the line (BEOL) processing, in accordance with another embodimentof the present disclosure.

FIG. 10 is a side cross-sectional view depicting patterning theinterlevel dielectric layers depicted in FIG. 9 to a provide viasextending to a seed surface portion of the bulk semiconductor substrate,in accordance with one embodiment of the present disclosure.

FIG. 11 is a side cross-sectional view depicting epitaxially forming anoptoelectronic light emission device, and an optoelectronic lightdetection device, wherein at least one material layer of at least one ofthe optoelectronic light emission device and the optoelectronic lightdetection device is epitaxial grown from the seed surface of thesubstrate.

FIG. 12 is a side cross-sectional view depicting forming the dielectricmaterial for the dielectric waveguide on the structure depicted in FIG.11.

FIG. 13 is a side cross-sectional view depicting pattering thedielectric material layer depicted in FIG. 12 to provide a dielectricwave guide, in accordance with one embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Detailed embodiments of the claimed structures and methods are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely illustrative of the claimed structures and methods that maybe embodied in various forms. In addition, each of the examples given inconnection with the various embodiments is intended to be illustrative,and not restrictive. Further, the figures are not necessarily to scale,some features may be exaggerated to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the methods and structures of the present disclosure. Forpurposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the embodiments of the disclosure,as it is oriented in the drawing figures. The terms “present on”, and“over” mean that a first element, such as a first structure, is presenton a second element, such as a second structure, wherein interveningelements, such as an interface structure, e.g. interface layer, may bepresent between the first element and the second element. The terms“direct contact”, “directly on” and “contacting” mean that a firstelement, such as a first structure, and a second element, such as asecond structure, are connected without any intermediary conducting,insulating or semiconductor layers at the interface of the two elements.

In some embodiments, the methods and structures disclosed herein provideoptoelectronic devices, e.g., an optoelectronic light emission deviceand an optoelectronic light detection device, which are composed ofIII-V semiconductor materials, and function as an optical interconnectin the transmission of data from one semiconductor device to anotheracross semiconductor substrate that may include material layers of typeIV semiconductor compositions. It has been determined that datatransmission across physical electrical communication structures, suchas vias, lines, and bus bars, is slow when compared to data transmissionusing optical interconnects, i.e., data via transmission of lightsignals. In some embodiments, the methods and structures disclosedherein replace the bus-bar that typically provides for electricalcommunication between semiconductor devices in a complementary metaloxide semiconductor (CMOS) arrangement with an optical interconnect toincrease the speed of data transmission to and from the semiconductordevices present on the substrate.

As used herein, the term “semiconductor device” refers to an intrinsicsemiconductor material that has been doped, that is, into which a dopingagent has been introduced, giving it different electrical propertiesthan the intrinsic semiconductor. Doping involves adding dopant atoms toan intrinsic semiconductor, which changes the electron and hole carrierconcentrations of the intrinsic semiconductor at thermal equilibrium.Dominant carrier concentration in an extrinsic semiconductor determinesthe conductivity type of the semiconductor. In some embodiments, thesemiconductor device may be a field effect transistor (FET). As usedherein a “field effect transistor” is a transistor in which outputcurrent, i.e., source-drain current, is controlled by the voltageapplied to the gate. A field effect transistor has three terminals,i.e., gate, source and drain. It is noted that the field effecttransistor is only one type of semiconductor device that is within thescope of the present disclosure, and it is not intended that thesemiconductor devices employed in the methods and structures of thepresent disclosure be limited to only FETs. For example, thesemiconductor devices may be any switching device including, but notlimited to, fin field effect transistor (FinFET), metal oxidesemiconductor field effect transistor (MOSFET), bipolar junctiontransistor (BJT), Schottky barrier semiconductor device, junction fieldeffect transistor (JFET), and combinations thereof. In other examples,the semiconductor device may be a memory device. As used herein, theterm “memory device” means a structure in which the electrical state canbe altered and then retained in the altered state, in this way a bit ofinformation can be stored. Examples of memory devices that may beemployed in the present disclosure include flash memory, dynamic randomaccess memory and combinations thereof.

In some embodiments, the semiconductor devices may be configured incomplementary metal-oxide-semiconductor (CMOS) arrangement. The word“complementary” refer to the fact that the typical digital design stylewith CMOS uses complementary and symmetrical pairs of p-type and n-typemetal oxide semiconductor field effect transistors (MOSFETs) for logicfunctions. CMOS technology is used in microprocessors, microcontrollers,static RAM, and other digital logic circuits. CMOS technology is alsoused for several analog circuits such as image sensors (CMOS sensor),data converters, and highly integrated transceivers for many types ofcommunication.

The optical interconnects disclosed herein include at least oneoptoelectronic light emission device for emitting a data signal using anemission of light, and at least one optoelectronic light detectiondevice for receiving the data signal being transmitted by theoptoelectronic light emission device as an emission of light.

As used herein, the term “optoelectronic light emission device” denotesa semiconductor light emitting structure, such as a laser diode. Thelaser diode is an electrically pumped semiconductor laser in which theactive medium is formed by a p-n junction of a semiconductor diodesimilar to that found in a light-emitting diode. A laser diode iselectrically a p-i-n diode. The active region of the laser diode is inthe intrinsic (I) region, and the carriers, electrons and holes, arepumped into it from the N and P regions (n-type doped regions or p-typedoped regions) respectively, also referred to herein as the first III-Vsemiconductor material layer and second III-V semiconductor materiallayer.

In some embodiments, the optoelectronic light emission device may be aquantum well laser. A quantum well laser is a laser diode in which theactive region of the device is so narrow that quantum confinementoccurs. If the middle layer, i.e., active region, of the laser is madethin enough, it acts as a quantum well. This means that the verticalvariation of the electron's wavefunction, and thus a component of itsenergy, is quantized. The term “quantum well” or “QW” used herein refersto a thin-layer structure comprising alternate layers consisting of afirst semiconductor layer with a thickness smaller than the de Brogliewavelength of about 200 Å to 300 Å with respect to electrons or holes,and at least a second semiconductor layer with a band gap greater thanthat of the first semiconductor layer. The term “band gap” refers to theenergy difference between the top of the valance band (i.e., Ev) and thebottom of the conduction band (i.e., Ec). A QW structure can be formedby sandwiching a semiconductor thin layer of a narrow band gap betweensemiconductor layers of a large band gap. Lasers containing more thanone quantum well layer are known as multiple quantum well lasers.

If a single semiconductor thin layer constitutes a quantum well for bothelectrons and holes, the quantum well is called a type I quantum well.In this case, the semiconductor layer of a narrow band gap is called awell layer, and the semiconductor layers of a large band gap are calledbarrier layers. A type I multi-quantum well structure can be formed byalternately laminating semiconductor layers of narrow and broad bandgaps. A type II quantum well structure has a first semiconductor layerforming a quantum well for electrons, a second semiconductor layerforming a quantum well for holes formed on the first semiconductor layerand third semiconductor layers sandwiching the first and secondsemiconductor layers as barrier layers to the electrons and holes. Atype II multi-quantum well structure can be formed by alternatelylaminating first semiconductor layers, second semiconductor layers andthird semiconductor layers. Optoelectronic light emission devicesincluding both type I and type II quantum wells are within the scope ofthe present disclosure.

The term “waveguide” as used herein, denotes a structure that receiveslight signals from a first optoelectronic device, e.g., optoelectroniclight emission device, and directs the light signal to a secondoptoelectronic device, e.g., optoelectronic light detection device.Examples of materials that are suitable for the dielectric waveguideinclude, without limitation, silicon oxides (e.g., doped or undopedsilicon dioxide, SiO₂), silicon nitride, silicon oxynitride, siliconcarbide, hafnium oxide, aluminum oxide, and silica.

The term “optoelectronic light detection device” as used herein, denotesa semiconductor containing photodetector. For example, theoptoelectronic light detection device may be composed of a III-Vsemiconductor material, such as GaInAs, and may function as an infrareddetector. Detection of a light signal may include conversion of thelight signal into an electrical signal. GaInAs photodiodes are exampleof an optoelectronic light detection device in accordance with thepresent disclosure that may be used to detect wavelengths ranging from1.1 μm to 1.7 μm. In other embodiments, the photodetector may becomposed of III-V semiconductor materials that can be employed fordetection of telecom wavelengths, i.e., wavelengths ranging from 1.31 μmto 1.55 μm. In some embodiments, the optoelectronic light detectiondevice can be a III-V pin photodetector. For example, the III-V pinphotodetector may include a p-type conductivity semiconductor layer,e.g., p-InGaAs layer, at least one intrinsic semiconductor layer, e.g.,i-InGaAs layer, and an n-type conductivity semiconductor layer, e.g.,n-InGaAs layer. In one example, the III-V pin photodetector may beprovided by an i-InGaAs layer serving as the intrinsic absorption layerthat is sandwiched between an n-InP layer and a p-InGaAs layer. Then-type and p-type conductivity layers that are on opposing sides of theintrinsic absorption layer in a III-V pin photodetector may be referredto as cladding layers.

Further details regarding the above described optoelectronic devices,e.g., optoelectronic light emission device and optoelectronic lightdetection device, semiconductor devices and waveguides are now describedwith reference to FIGS. 1-13.

FIG. 1 depicts one embodiment of an electrical device that including anoptical interconnect 15, 25, 35 forming on a semiconductor on insulator(SOI) substrate 5. The SOI substrate 5 typically includes at least onetype IV semiconductor material layer. The term “type IV” as used todescribe a semiconductor material means that the semiconductor materialis in Group IV of the Periodic Table of Elements (Group 14 in accordancewith the IUPAC system). As will be described below, the type IVsemiconductor material that provides the seed surface for laterdescribed epitaxially grown III-V semiconductor materials is typicallycomposed of a silicon containing material, but the present disclosure isnot limited to only this example, as germanium containing substrates andsilicon carbide containing substrates are also within the scope of thepresent disclosure. Any substrate material that meets the definition ofa type IV semiconductor substrate is within the scope of the presentdisclosure.

In one embodiment, the SOI substrate 5 typically includes asemiconductor on insulator (SOI) layer 4 that is present on a burieddielectric layer 3, wherein the buried dielectric layer 3 is present ona base semiconductor substrate 2. The SOI layer 4 of the SOI substrate 5may be composed of any type IV semiconductor material, such as silicon,monocrystalline silicon, polycrystalline silicon, silicon germanium,monocrystalline silicon germanium, polycrystalline silicon germanium,silicon doped with carbon (Si:C), silicon carbide, silicon germaniumdoped with carbon (SiGe:C) and combinations thereof. In otherembodiments, the SOI layer 4 may be composed of a type III-Vsemiconductor material, such as, GaAs, InAs, InP as well as other III/Vand II/VI compound semiconductors. The SOI layer 4 may have a thicknessranging from 10 nm to 250 nm. In some embodiments, in which the SOIlayer 4 is an extremely thin SOI layer (ETSOI layer), the thickness ofthe SOI layer 4 may be less than 10 nm.

The buried dielectric layer 3 may be composed of any oxide, nitride oroxynitride dielectric material. For example, when the buried dielectriclayer 3 is an oxide, the buried dielectric layer 3 may be composed ofsilicon oxide. In another example, when the buried dielectric layer 3 isa nitride, the buried dielectric layer 3 may be silicon nitride. Thethickness of the buried dielectric layer 3 may range from 10 nm to 250nm. The base semiconductor substrate 2 may be composed of any type IVsemiconductor material including, but not limited to Si, strained Si,SiC, SiGe, SiGeC, Si alloys, Ge, Ge alloys and combinations thereof. Inother embodiments, the base semiconductor substrate 2 may be composed ofa type III-V semiconductor material, such as, GaAs, InAs, InP as well asother III/V and II/VI compound semiconductors. The base semiconductorlayer 2 may have the same or a different composition than the SOI layer4.

A first portion 20 of the SOI substrate 5 contains a first semiconductordevice 10. A second portion 30 of the SOI substrate 5 contains anoptical interconnect, which includes an optoelectronic light emissiondevice 15, a dielectric waveguide 25, and an optoelectronic lightdetection device 35. A third portion 45 of the SOI substrate 5 containsa second semiconductor device 40.

The first and second semiconductor devices 10, 40 may be any switchingor memory type device, as described above. In the embodiment that isdepicted in FIG. 1, the first and second semiconductor devices 10, 40each include a source region 11 a, 11 b, and a drain region 12 a, 12 bon opposing sides of a gate structure 13 a, 13 b. In some embodiments,the source and drain regions 11 a, 11 b, 12 a, 12 b are formed, i.e.,present, within a remaining portion of the SOI layer 4 in each of thefirst and third portions 20, 45 of the SOI substrate 5. As used herein,the term “source” is a doped region in the semiconductor device, inwhich majority carriers are flowing into the channel. As used herein,the term “channel” is the region underlying the gate structure andbetween the source and drain of a semiconductor device that becomesconductive when the semiconductor device is turned on. As used herein,the term “drain” means a doped region in semiconductor device located atthe end of the channel, in which carriers are flowing out of thetransistor through the drain. A “gate structure” means a structure usedto control output current (i.e., flow of carriers in the channel) of asemiconducting device through electrical or magnetic fields. The gatestructures 13 a, 13 b typically include at least one gate dielectric 14a, 14 b that is present on the channel region portion of thesemiconductor device, and at least one gate conductor 16 a, 16 b.

The conductivity type of the source and drain regions 11 a, 11 b, 12 a,12 b typically dictates the conductivity type of the semiconductordevice 10, 40 to which the source and drain regions 11 a, 11 b, 12 a, 12b correspond. The term “conductivity type” denotes whether asemiconductor material has been doped to an n-type or p-typeconductivity. As used herein, “p-type” refers to the addition ofimpurities to an intrinsic semiconductor that creates deficiencies ofvalence electrons. In a type IV semiconductor material, such as the SOIlayer 4 of the SOI substrate 5, examples of n-type dopants, i.e.,impurities, include but are not limited to: boron, aluminum, gallium andindium. As used herein, “n-type” refers to the addition of impuritiesthat contributes free electrons to an intrinsic semiconductor. In a typeIV semiconductor material, such as the SOI layer 4 of the SOI substrate5, examples of n-type dopants, i.e., impurities, include but are notlimited to antimony, arsenic and phosphorous.

In some embodiments, the first semiconductor device 10 may have a sourceregion 11 a and a drain region 12 a doped to an n-type conductivity,i.e., first conductivity type, to provide an n-type FET, i.e., firstconductivity FET, and the second semiconductor device 40 may have asource region 11 b and drain region 12 b doped to a p-type conductivity,i.e., second conductivity type to provide a p-type FET, i.e., secondconductivity FET. In some embodiments, the first semiconductor device 10may have a source region 11 a and a drain region 12 a doped to a p-typeconductivity, i.e., first conductivity type, to provide a p-type FET,and the second semiconductor device 40 may have a source region 11 b anddrain region 12 b doped to an n-type conductivity, i.e., secondconductivity type to provide an n-type FET. In some examples, when thefirst semiconductor device 10 has a first conductivity type, and thesecond semiconductor device 40 has a second conductivity type that isdifferent from the first conductivity type, the first and secondsemiconductor devices 10, 40 may be referred to as being in a CMOSarrangement.

The at least one gate dielectric 14 a, 14 b for each of the gatestructures 13 a, 13 b for the first semiconductor device 10 and thesecond semiconductor device 40 can be comprised of a semiconductoroxide, semiconductor nitride, semiconductor oxynitride, or anymultilayered stack thereof. In one example, the at least one gatedielectric 14 a, 14 b can be comprised of a semiconductor oxide such as,e.g., silicon dioxide. The at least one gate dielectric 14 a, 14 b canalso be comprised of a dielectric metal oxide having a dielectricconstant that is greater than the dielectric constant of silicondioxide, e.g., 3.9. The dielectric constants that are described hereinare measured at room temperature, i.e., 25° C., at atmospheric pressure,i.e., 1 atm. In one embodiment, the at least one gate dielectric 14 a,14 b can comprise a dielectric oxide having a dielectric constantgreater than 4.0. In another embodiment, the at least one gatedielectric 14 a, 14 b can be comprised of a dielectric oxide having adielectric constant of greater than 8.0. Exemplary dielectric oxidematerials which have a dielectric constant of greater than 3.9 include,but are not limited to HfO₂, ZrO₂, La₂O₃, Al₂O₃, TiO₂, SrTiO₃, LaAlO₃,Y₂O₃, HfO_(x)N_(y), ZrO_(x)N_(y), La₂O_(x)N_(y), Al₂O_(x)N_(y),TiO_(x)N_(y), SrTiO_(x)N_(y), LaAlO_(x)N_(y), Y₂O_(x)N_(y), a silicatethereof, and an alloy thereof. Each value of x is independently from 0.5to 3 and each value of y is independently from 0 to 2. In someembodiments, multilayered stacks of at least two of the above mentioneddielectric materials can be employed as the at least one gate dielectriclayer 14 a, 14 b. For example, the at least one gate dielectric 14 a, 14b can include a stack of, from bottom to top, silicon dioxide andhafnium oxide.

The at least one gate conductor 16 a, 16 b may be composed of conductivematerials including, but not limited to metals, metal alloys, metalnitrides and metal silicides, as well as laminates thereof andcomposites thereof. In one embodiment, the at least one gate conductor16 a, 16 b may be any conductive metal including, but not limited to W,Ni, Ti, Mo, Ta, Cu, Pt, Ag, Au, Ru, Jr, Rh, and Re, and alloys thatinclude at least one of the aforementioned conductive elemental metals.The at least one gate conductor 16 a, 16 b may also comprise dopedpolysilicon and/or polysilicon-germanium alloy materials (i.e., having adopant concentration from 1×10¹⁸ dopant atoms per cubic centimeter to1×10²² dopant atoms per cubic centimeter) and polycide materials (dopedpolysilicon/metal silicide stack materials).

A gate sidewall spacer 17 may be present on the sidewall of the gatestructures 13 a, 13 b. The gate sidewall spacer 17 may be composed of anoxide, nitride, or oxynitride material.

Referring to FIG. 1, the first and second semiconductor devices 10, 40are typically covered by at least one interlevel dielectric layer 21,22, 23, 24. The at least one interlevel dielectric layer 21, 22, 23, 24may extend across an entirety of the SOI substrate 5, wherein the atleast one interlevel dielectric layer 21, 22, 23, 24 is present in eachof the first portion 20, second portion 30 and third portion 45 of theSOI substrate 5. The composition of each layer in the plurality of theinterlevel dielectric layers 21, 22, 23, 24 is selected to allow forselective etching between the adjacent dielectric layers during theformation of later described interconnect wiring. Compositions that aresuitable for the interlevel dielectric layers may be selected from thegroup consisting of silicon containing materials such as SiO₂, Si₃N₄,SiO_(x)N_(y), SiC, SiCO, SiCOH, and SiCH compounds, the above-mentionedsilicon containing materials with some or all of the Si replaced by Ge,carbon doped oxides, inorganic oxides, inorganic polymers, hybridpolymers, organic polymers such as polyamides or SiLK™, other carboncontaining materials, organo-inorganic materials such as spin-on glassesand silsesquioxane-based materials, and diamond-like carbon (DLC), alsoknown as amorphous hydrogenated carbon, α-C:H). Additional choices forthe interlevel dielectric layer 21, 22, 23, 24 include any of theaforementioned materials in porous form, or in a form that changesduring processing to or from being porous and/or permeable to beingnon-porous and/or non-permeable.

In some embodiments, the interlevel dielectric layers identified byreference numbers 21, 22, 23 provide a first level 70 of the electricaldevice in which the first and second semiconductor devices 10, 40 arepresent. As will be described in greater detail below, the opticalinterconnect composed of the optoelectronic light emission device 15,dielectric waveguide 25, and optoelectronic light detection device 35 ispositioned on an upper surface of the upper most interlevel dielectriclayer 23 of the first level 70. The optical interconnect is covered withan interlevel dielectric layer identified by reference number 24, andpresent in a second level 75 of the electrical device. As depicted inFIG. 1, the optical interconnect that is present in the second level 75of the electrical device is laterally offset from the first and secondsemiconductor devices 10, 40 that are present in the first level 70 ofthe electrical device.

The second portion 30 of the SOI substrate 5 has been processed toprovide the optical interconnect providing for data transmission betweenthe first and second semiconductor devices 10, 40, wherein the opticalinterconnect includes the optoelectronic light emission device 15, thedielectric waveguide 25, and the optoelectronic light detection device35. In some embodiments, at least base material layers for theoptoelectronic light emission device 15 and the optoelectronic lightdetection device 35 of the optical interconnect are formed using anepitaxial growth process, in which epitaxial material is grown from aseed surface of the SOI substrate 5 through a via 76 that extendsthrough the interlevel dielectric layers 21, 22, 23 of the first level70, wherein the epitaxial material extends from the opening of the via76 laterally over and in direct contact with the uppermost interleveldielectric layer 23 of the first level 70. In some embodiments, the via76 also extends through the buried dielectric layer 3 of the SOIsubstrate 5 to expose a portion of the base semiconductor substrate 2 toprovide the seed surface for epitaxial growth of the material for atleast the base material layers for the optoelectronic light emissiondevice 15 and the optoelectronic light detecting device 35. In someembodiments, at least one via 76 that is filled with epitaxial materialis present at the interface between the first portion 20 of the SOIsubstrate 5 and the second portion 30 of the SOI substrate 5. In someembodiments, at least one via 76 that is filled with epitaxial materialis present at the interface between the second portion 30 of the SOIsubstrate 5 and the third portion 45 of the SOI substrate 5.

In some embodiments, the optoelectronic light emission device 15 may bea laser diode composed of III-V compound semiconductors. As used herein,the term “III-V compound semiconductor” denotes a semiconductor materialthat includes at least one element from Group III of the Periodic Tableof Elements (Group 13 in accordance with the IUPAC system), and at leastone element from Group V of the Periodic Table of Elements (Group 15 inaccordance with the IUPAC system).

Examples of III-V compound semiconductor materials that can be employedin the material layers of the optoelectronic light emission device 15include (AlSb), aluminum arsenide (AlAs), aluminum nitride (AlN),aluminum phosphide (AlP), gallium arsenide (GaAs), gallium phosphide(GaP), indium antimonide (InSb), indium arsenic (InAs), indium nitride(InN), indium phosphide (InP), aluminum gallium arsenide (AlGaAs),indium gallium phosphide (InGaP), aluminum indium arsenic (AlinAs),aluminum indium antimonide (AlInSb), gallium arsenide nitride (GaAsN),gallium arsenide antimonide (GaAsSb), aluminum gallium nitride (AlGaN),aluminum gallium phosphide (AlGaP), indium gallium nitride (InGaN),indium arsenide antimonide (InAsSb), indium gallium antimonide (InGaSb),aluminum gallium indium phosphide (AlGaInP), aluminum gallium arsenidephosphide (AlGaAsP), indium gallium arsenide phosphide (InGaAsP), indiumarsenide antimonide phosphide (InArSbP), aluminum indium arsenidephosphide (AlInAsP), aluminum gallium arsenide nitride (AlGaAsN), indiumgallium arsenide nitride (InGaAsN), indium aluminum arsenide nitride(InAlAsN), gallium arsenide antimonide nitride (GaAsSbN), gallium indiumnitride arsenide aluminum antimonide (GaInNAsSb), gallium indiumarsenide antimonide phosphide (GaInAsSbP), and combinations thereof.

Laser diodes are formed in compound semiconductor materials, such asIII-V semiconductor materials, that are able to emit light. In oneembodiment, the laser diode that provides the optoelectronic lightemission device 15 includes a first conductivity type III-Vsemiconductor material layer 15 a that is present directly on the uppersurface of the uppermost interlevel dielectric layer 23 of the firstlevel 70 of the electronic device, a stacked structure of quantum wells15 b comprising III-V semiconductor material layers that is present onthe first conductivity type III-V semiconductor material layer 15 a, anda second conductivity type III-V semiconductor material layer 15 b thatis present on the stacked structure of quantum wells 12.

The optoelectronic light emission device 15 depicted in FIG. 1 is aquantum well laser, in which the wavelength of the light emitted by thequantum well laser is determined by the width of the active regionrather than just the bandgap of the material from which it isconstructed. The first and second conductivity type III-V semiconductormaterial layers 15 a, 15 c, which may also be referred to as claddinglayers, typically are doped to a first conductivity type and an opposingsecond conductivity type. For example, the first conductivity type III-Vsemiconductor material layer 15 a may be doped to a first conductivity,e.g., n-type conductivity, and the second conductivity type III-Vsemiconductor material layer 15 c may be doped to a second conductivity,e.g., p-type conductivity.

In some embodiments, the first and second conductivity type III-Vsemiconductor material layers 15 a, 15 c function to pump chargecarriers, i.e., electron and hole charge carriers, into the intrinsicactive area provided by the quantum well. In some examples, the firstconductivity type III-V semiconductor material layer 15 a may becomposed of InP, GaAs, AlGaAs, InAlAs or a combination thereof. Thedopant that provides the conductivity type, i.e., first typeconductivity, e.g., n-type, of the first conductivity type III-Vsemiconductor material layer 15 a may be present in a concentrationranging from 10¹⁷ atoms/cm³ to 10²⁰ atoms/cm³. In some examples, thefirst conductivity type III-V semiconductor material layer 15 a may havea thickness ranging from 100 nm to 2000 nm. In some embodiments, thesecond conductivity type III-V semiconductor material layer 15 b may becomposed of InP or GaAs or AlGaAs or InAlAs. The dopant that providesthe conductivity type, i.e., second type conductivity, e.g., p-type, ofthe second conductivity type III-V semiconductor material layer 15 b maybe present in a concentration ranging from 10¹⁷ atoms/cm³ to 10²⁰atoms/cm³. In some examples, the second conductivity type III-Vsemiconductor material layer 15 c may have a thickness ranging from 100nm to 2000 nm. It is noted that the above compositions and thicknessesare provided for illustrative purposes only, and are not intended tolimit the present disclosure. For example, the first and secondconductivity type III-V semiconductor material layers 15 a, 15 c may becomposed of any III-V compound semiconductor composition provided above.

The active region of the laser diode is in the intrinsic (I) region. By“intrinsic” it is meant that the region is not doped with an extrinsicdopant, e.g., n-type or p-type dopant, such as the dopants used to dopethe first and second conductivity type III-V semiconductor materiallayers 15 a, 15 c. The active region in the quantum well structure 15 bis formed by alternating layers of relatively low bandgap material andlayers of relatively high bandgap material. As used herein, a “lowbandgap” is a bandgap ranges from 0.5 eV to 3.0 eV, and a “high bandgap”ranges from 1.0 eV to 3.5 eV. The former layers are termed “well layers”and the latter layers are termed “barrier layers.” For example, theactive low bandgap layers comprised Al_(r)Ga_(1-r)As and the passivehigh bandgap layers comprised Al_(z) Ga_(1-z)As with r<z.

To provide the stacked structure of quantum wells 15 b, the thickness ofeach layer of III-V compound semiconductor material within the quantumwell 15 b may be no greater than 50 nm. For example, the thickness foreach layer of the III-V compound semiconductor material within thequantum well 15 b may range from 5 nm to 10 nm. In some embodiments, thestacked structure of quantum wells 15 b may be composed of 1 to 100layers of semiconductor material, such as III-V compound semiconductormaterial. In yet another embodiment, the stacked structure of quantumwells 15 b may be composed of 1 to 5 layers of semiconductor material.In some embodiments, the quantum well (QW) layers and barrier layers ofthe quantum well structure 15 b are formed of a semiconductor material,such asIn_(x)Ga_(1-x)As_(y)P_(1-y), In_(x)Ga_(1-x)As,In_(x)Ga_(1-x)N_(y)As_(1-y), In_(x)Ga_(1-x)As_(y)Sb (here, 0.0<x<1.0,0.0<y<1.0).

Referring to FIG. 8, the optoelectronic light emission device 15 mayhave a width W3 ranging from 3 microns to 5 microns. The width W3dimension of the optoelectronic light emission device 15 is along adimension perpendicular to the direction along which the optoelectroniclight emission device 15 emits a beam of light. In some embodiments, thewidth W3 may range from 3.75 microns to 4.25 microns, and in one exampleis equal to 4 microns. The length L2 of the optoelectronic lightemission device 15 may range from approximately 50 microns toapproximately 100 microns. In one example, the length L2 of theoptoelectronic light emission device 15 may be approximately 80 microns.

Referring to FIG. 1, in some embodiments, the end of the active portionof the SOI layer 4 that provides the source or drain region 11 a, 12 aof the first semiconductor device 10 is separated, and electricallyisolated, from the via 27 of the epitaxial material to the opticalinterconnect by an isolation dielectric material 19. The isolationdielectric material 19 may be composed of any dielectric material. Insome examples, the isolation dielectric material 19 may composed of anoxide, such as silicon oxide (SiO₂). In another example, the isolationdielectric material 19 may be composed of a nitride, such as siliconnitride. It is noted that the above examples are provided forillustrative purposes only, and that other dielectric compositions maybe suitable for the isolation dielectric material 19.

The dielectric wave guide 25 is positioned in direct contact with anupper surface of the uppermost interlevel dielectric layer 23 and ispositioned between the optoelectronic light emission device 15 and theoptoelectronic light detecting device 35 in the second portion 20 of theSOI substrate 5. The dielectric waveguide 25 is present overlying theburied dielectric layer 3 of the SOI substrate 5, wherein at least threeinterlevel dielectric layers 21, 22, 23 are present between thedielectric waveguide 25 and the buried dielectric layer 3 of the SOIsubstrate 5.

Typically, the function of the dielectric wave guide 25 is to receivethe beam of light being emitted from the optoelectronic light emissiondevice 15 and to transmit that beam of light to the optoelectronic lightdetection device 35. In some embodiments, the dielectric wave guide 25is composed of a dielectric material that is selected from the groupconsisting of silicon oxide, silicon nitride, silicon oxynitride,silicon carbide, hafnium oxide, aluminum oxide, aluminum nitride,amorphous silicon, silica and combinations thereof. The dielectric waveguide 25 typically has a tapered geometry, as depicted in FIG. 8. By“tapered” it is meant that the width of the dielectric wave guide 25decreases along one direction from a first end of the dielectric waveguide 25 to a second end of the dielectric wave guide 25. For example,in some embodiments, the face of the dielectric wave guide 25 that isproximate to, and receives the light from the optoelectronic lightemission device 15, is typically greater in width W1 than the width W2of the face of the dielectric wave guide 25 that transmits the light tooptoelectronic light detection device 35. The width of the dielectricwave guide 25 may taper gradually at a consistent rate, or the taper ofthe dielectric wave guide 25 may have regions in which the rate that thewidth of the dielectric wave guide 25 decreases is greater than thetaper in other portions of the dielectric wave guide 25. In one example,the width W1 of the face of the dielectric wave guide 25 that receivesthe light beam from the optoelectronic light emission device 15 mayrange from 4 microns to 16 microns. In another embodiment, the width W1of the face of the dielectric wave guide 25 that is adjacent to the faceof the optoelectronic light emission device 15 ranges from 6 microns to10 microns, e.g., the width W1 of the face of the dielectric wave guide15 adjacent to the optoelectronic light emitted device 15 may be 8microns. In one example, the width W2 of the face of the dielectric waveguide 15 that emits the light beam may range from 1 micron to 8 microns.In another example, the width W2 of the face of the dielectric waveguide 15 that emits the light beam and is adjacent to the optoelectroniclight detection device 35 ranges from 1 micron to 5 microns.

Referring to FIG. 8, the dielectric wave guide 25 is positioned to havea length L1 along the direction that light is being emitted from theoptoelectronic light emission device 15. The length L1 of the dielectricwave guide 25 is positioned to be align the light being emitted from theoptoelectronic light emission device 15 to the optoelectronic lightdetection device 35. In this manner, the dielectric wave guide 25 issubstantially aligned with the light being emitted from theoptoelectronic light emission device 15 and is substantially aligned todirect the light received from the optoelectronic light emission device15 to the optoelectronic light detection device 35. The length L1 of thedielectric wave guide 25 may range from 50 microns to 100 microns. Insome embodiments, the length L1 of the dielectric wave guide 25 mayrange from 60 microns to 90 microns. For example, the length L1 of thedielectric wave guide 25 may be 80 microns.

The distance separating the emission face of the optoelectronic lightemission device 15 from the receiving face of the dielectric wave guide25 may range from 100 nm to 300 nm. In one example, the distanceseparating the optoelectronic light emission device 15 from the emissionface of the dielectric wave guide 25 is equal to 200 nm. The distanceseparating the emission face of the optoelectronic light detectiondevice 35 from the emitting face of the dielectric wave guide 25 mayrange from 100 nm to 300 nm. In one example, the distance separating theoptoelectronic light detection device 35 from the receiving face of thedielectric wave guide 25 is equal to 200 nm.

Referring to FIG. 1, the optoelectronic light detection device 35 ispresent within the second portion 30 of the SOI substrate 5 on theopposing side of the dielectric waveguide 25 that the optoelectroniclight emission device 15 is present on. The optoelectronic lightdetection device 35 may be a photodetector composed of III-V compoundsemiconductors. Examples of III-V compound semiconductor materials thatcan be employed in the material layers of the optoelectronic lightdetection device 35 include (AlSb), aluminum arsenide (AlAs), aluminumnitride (AlN), aluminum phosphide (AlP), gallium arsenide (GaAs),gallium phosphide (GaP), indium antimonide (InSb), indium arsenic(InAs), indium nitride (InN), indium phosphide (InP), aluminum galliumarsenide (AlGaAs), indium gallium phosphide (InGaP), aluminum indiumarsenic (AlInAs), aluminum indium antimonide (AlInSb), gallium arsenidenitride (GaAsN), gallium arsenide antimonide (GaAsSb), aluminum galliumnitride (AlGaN), aluminum gallium phosphide (AlGaP), indium galliumnitride (InGaN), indium arsenide antimonide (InAsSb), indium galliumantimonide (InGaSb), aluminum gallium indium phosphide (AlGaInP),aluminum gallium arsenide phosphide (AlGaAsP), indium gallium arsenidephosphide (InGaAsP), indium arsenide antimonide phosphide (InArSbP),aluminum indium arsenide phosphide (AlInAsP), aluminum gallium arsenidenitride (AlGaAsN), indium gallium arsenide nitride (InGaAsN), indiumaluminum arsenide nitride (InAlAsN), gallium arsenide antimonide nitride(GaAsSbN), gallium indium nitride arsenide aluminum antimonide(GaInNAsSb), gallium indium arsenide antimonide phosphide (GaInAsSbP),and combinations thereof. The photodetector converts the light signalinto electrical signal. If the light is modulated at the emitter, thephotodetector reconstructs this modulation back into the electricaldomain.

In some embodiments, the optoelectronic light detection device 35includes a first conductivity type III-V semiconductor layer 35 a, anintrinsic III-V semiconductor material layer 35 b, and a secondconductivity type III-V semiconductor material layer 35 c. The firstconductivity type III-V semiconductor material layer 35 a may becomposed of an epitaxial material that is epitaxially grown from thesemiconductor seed surface of the SOI substrate 5. The epitaxialmaterial for the first conductivity type III-V semiconductor materiallayer 35 a may be grown from the semiconductor seed surface to fill thevia 76, and extend from the opening to the via 76 over the upper surfaceof the uppermost interlevel dielectric layer 23 of the first level 70 ofthe electrical device. In this manner, the first conductivity type III-Vsemiconductor material layer 35 a may be the base material layer of theoptoelectronic light detection device 35.

The first conductivity type III-V semiconductor material layer 35 a ofthe optoelectronic light detection device 35 may be doped to an n-typeconductivity. The n-type dopant that may be present in the firstconductivity type III-V semiconductor material layer 35 a in aconcentration ranging from 1×10¹⁷ cm⁻³ to 1×10²⁰ cm⁻³. In someembodiments, the composition of the first conductivity type III-Vsemiconductor material layer 35 a may be selected from the groupconsisting of GaAs, InP, AlGaAs, InAlAs, and combinations thereof. Thefirst conductivity type III-V semiconductor material layer 35 a may havea thickness ranging from 1.0 micron to 2.0 microns.

The intrinsic III-V semiconductor material layer 35 b of theoptoelectronic light detection device 35 is typically undoped, but mayinclude some unintentional dopant from the first and second conductivitytype III-V semiconductor material layers 35 a, 35 c that results fromdiffusion effects. The maximum concentration of n-type or p-type dopantthat may unintentionally be present in the intrinsic III-V semiconductormaterial layer 35 b can be equal to 5×10¹⁶ cm⁻³. The intrinsic III-Vsemiconductor material layer 35 b may be composed of at least one ofGaAs, InP, AlGaAs, InAlAs and combinations thereof. The intrinsic III-Vsemiconductor material layer 35 b may be composed of a singlecomposition or may be a multi-layered structure of multiplecompositions. The thickness of the III-V semiconductor material layer 35b may range from 10 nm to 1000 nm. The intrinsic III-V semiconductormaterial layer 35 b may be present directly on an upper surface of thefirst conductivity type III-V semiconductor material layer 35 a.

The second conductivity type III-V semiconductor material layer 35 c ofthe optoelectronic light detection device 35 may have an oppositeconductivity type of the first conductivity type III-V semiconductormaterial layer 35 a. For example, the second conductivity type III-Vsemiconductor material layer 35 c may have a p-type conductivity. Thep-type dopant that may be present in the second conductivity type III-Vsemiconductor material layer 35 c in a concentration ranging from 1×10¹⁷cm⁻³ to 1×10²⁰ cm⁻³. In some embodiments, the composition of the secondconductivity type III-V semiconductor material layer 35 c may beselected from the group consisting of GaAs, InP, AlGaAs, InAlAs, andcombinations thereof. The second conductivity type III-V semiconductormaterial layer 35 c may have a thickness ranging from 1.0 micron to 2.0microns. The second conductivity type III-V semiconductor material layer35 c is present in direct contact with the second intrinsic III-Vsemiconductor layer 35 b.

Referring to FIG. 8, the optoelectronic light detection device 35 mayhave a width W4 ranging from 3 microns to 5 microns. The width W4dimension of the optoelectronic light detection device 35 is along adimension perpendicular to the direction along which the optoelectroniclight detection device 15 emits a beam of light. In some embodiments,the width W4 may range from 3.75 microns to 4.25 microns, and in oneexample is equal to 4 microns. The length L3 of the optoelectronic lightdetection device 35 may range from approximately 50 microns toapproximately 100 microns. In one example, the length L3 of theoptoelectronic light detection device 35 may be approximately 80microns.

The third portion 45 of the SOI substrate 5 includes the secondsemiconductor device 40. The second semiconductor device 40 has beendescribed above, and may have a conductivity type that is opposite theconductivity type of the first semiconductor device 10. For example,when the first semiconductor device 10 has an n-type conductivity, thesecond semiconductor device 40 has a p-type conductivity, and when thefirst semiconductor device 10 has a p-type conductivity, the secondconductivity semiconductor device 40 has an n-type conductivity. Asdepicted in FIG. 1, the second semiconductor device 40 may be a fieldeffect transistor (FET) that includes a gate structure 13 b, sourceregion 11 b and drain region 12 b. The description of the source region11 b, drain region 12 b and the gate structure 13 b including the atleast one gate conductor 16 b and the at least one gate dielectric 12 bhas been provided above. The source and drain regions 11 b, 12 b of thesecond semiconductor device 40 has been formed in the portion of the SOIlayer 4 that is present within the third portion 45 of the SOI substrate5. Referring to FIG. 1, in some embodiments, the end of the activeportion of the SOI layer 4 that provides the source or drain region 11b, 12 b of the second semiconductor device 40 is separated, andelectrically isolated, from the sidewall of the optoelectronic lightdetection device 35 by an isolation dielectric material 19.

In some embodiments, the end of the active portion of the SOI layer 4that provides the source or drain region 11 b, 12 b of the secondsemiconductor device 40 is separated, and electrically isolated, fromthe via 27 of the epitaxial material to the optical interconnect by anisolation dielectric material 19. The isolation dielectric material 19may be composed of any dielectric material. In some examples, theisolation dielectric material 19 may composed of an oxide, such assilicon oxide (SiO₂). In another example, the isolation dielectricmaterial 19 may be composed of a nitride, such as silicon nitride. It isnoted that the above examples are provided for illustrative purposesonly, and that other dielectric compositions may be suitable for theisolation dielectric material 19.

The electrical device further includes a plurality of interleveldielectric layers 21, 22, 23, 24 over the optical interconnect 15, 25,35, as well as the first and second semiconductor devices 10, 40. Theinterlevel dielectric layers 21, 22, 23, 24 are formed for deviceisolation, and are a part of the process for forming the interconnectwiring, i.e., vias 26 a, 26 b, 26 c, 26 d and lines 27 a, 27 b, 27 c, 27d that provide for electrical communication to the semiconductordevices, e.g., first and second semiconductor devices 10, 40, that arepresent on the SOI substrate 5. The interconnect wiring, i.e., vias 26a, 26 c and lines 27 a, 27 c, that are present in the first portion 20and the second portion 30 of the SOI substrate 5 also provide forelectrical communication between the first semiconductor device 10 andthe optoelectronic light emission device 15. The interconnect wiring,i.e., vias 26 b, 26 d and lines 27 b, 27 d, in the second portion 30 andthird portion 45 of the SOI substrate 5 provide for electricalcommunication between the optoelectronic light detection device 35 andthe second semiconductor device 40.

The interconnect wiring, i.e., vias 26 b and lines 27 b, may be composedof an electrically conductive material. “Electrically conductive” asused through the present disclosure means a material typically having aroom temperature conductivity of greater than 10⁻⁸(−m)⁻¹. For example,the interconnect wiring may be composed of a conductive metal. Theconductive metal may include, but is not limited to, tungsten, copper,aluminum, silver, gold and alloys thereof.

FIG. 2 depicts another embodiment of an electrical device in accordancewith the present disclosure. FIG. 2 depicts one embodiment of anelectrical device including three semiconductor devices 10, 40, 80present on a bulk semiconductor substrate 2 a, in which datatransmission between at least two of the devices, e.g., the first andsecond semiconductor devices 10, 20, includes an optical interconnect15, 25, 30. The embodiment depicted in FIG. 2 is similar to theembodiment that has been described above with reference to FIG. 1.Therefore, the description of the structures depicted in FIG. 1 havingreference numbers 10, 11 a, 11 b, 12 a, 12 b, 14 a, 14 b, 15, 15 a, 15b, 15 c, 16 a, 16 b, 24, 25, 25 a, 25 b, 25 c 26 a, 26 b, 26 c, 26 d, 27a, 27 b, 27 c, 27 d, 35, 35 a, 35 b, 35 c and 40 is suitable for thestructure depicted in FIG. 2 having the same reference numbers.

The substrate 2 a that is depicted in FIG. 2 is a bulk semiconductorsubstrate. The bulk semiconductor substrate is typically composedentirely of semiconductor material, e.g., does not include the burieddielectric layer of an SOI substrate. In some examples, the bulksemiconductor substrate may be composed of any type IV semiconductormaterial including, but not limited to Si, strained Si, SiC, SiGe,SiGeC, Si alloys, Ge, Ge alloys and combinations thereof. In otherembodiments, the bulk semiconductor substrate may be composed of a typeIII-V semiconductor material, such as, GaAs, InAs, InP as well as otherIII/V and II/VI compound semiconductors.

In some embodiments, a first semiconductor device 10 is positioned on afirst portion 20 of the substrate 2 a and a second semiconductor device40 positioned on a third portion 45 of the substrate 2 a, wherein thefirst and third portions 20, 45 of the substrate 2 a are separated by asecond portion 30 of the substrate 2 a. In some embodiments, the secondportion 30 of the substrate may include a third semiconductor device 80that is present on the same level, i.e., first level 70, of theelectrical device as the first and second semiconductor devices 10, 40.The third semiconductor device 80 is similar to the first and secondsemiconductor devices 10, 40. It is noted that the portion of thesubstrate that the third semiconductor device 80 is depicted as beingpresent on is not limited to only some semiconductor device. Forexample, a plurality of semiconductor and/or memory devices may bepresent on the portion of the semiconductor substrate that the thirdsemiconductor device 80 is present on.

For example, the third semiconductor device 80 may be any switching ormemory type device, as described above. In the embodiment that isdepicted in FIG. 2, the third semiconductor device 80 is a field effecttransistor (FET) that includes a source region 11 c and a drain region12 c on opposing sides of a gate structure 13 c. The description of thesource regions 11 a, 11 b, drain regions 12 a, 12 b, and the gatestructures 13 a, 13 b provided above for the first and secondsemiconductor devices 10, 40 is suitable for the description of thesource region 11 c, the drain region 12 c and the gate structure 13 c ofthe third semiconductor device 80 that is depicted in FIG. 2. The thirdsemiconductor device 80 may be an n-type or p-type conductivitysemiconductor device, e.g., n-type FET or p-type FET. The thirdsemiconductor device 80 may be positioned in the second portion of thesubstrate 2 a underlying the optical interconnect 15, 25, 35. The thirdsemiconductor device 80 is optional, and may be omitted in someembodiments.

At least one interlevel dielectric layer 21 a is present on the first,second and third portions 20, 30, 45 of the substrate 2 a, wherein theinterlevel dielectric layer 21 a is present over the first, second andthird semiconductor devices 10, 40, 80. In one example, the first,second and third semiconductor devices 10, 40, 80, as well as the vias26 a, 26 b, 26 e to the first, second and third semiconductor devices10, 40, 80 may be present in a first level 70 of the electrical devicethat includes the single interlevel dielectric layer 21 a. Although FIG.2. only depicts a single interlevel dielectric layer 21 a present overthe first and second semiconductor devices 10, 40, the presentdisclosure is not limited to only this embodiment.

The second portion 30 of the substrate 2 a further includes an opticalinterconnect 15, 25, 35 that is formed in a second level 75 of theelectrical device. The optical interconnect typically includes anoptoelectronic light emission device 15, a dielectric waveguide 25, andan optoelectronic light detection device 35. The optical interconnectdepicted in FIG. 2 is similar to the optical interconnect that isdepicted in FIG. 1. The vias 76 of epitaxial material extend to an uppersurface of the bulk substrate 2 a, which provides the seed surface forthe epitaxial material that provides the base material layer of theoptoelectronic light emission device 15, e.g., the first conductivitytype III-V semiconductor material layer 15 a of the optoelectronic lightemission device 15, and provides the base material layer of theoptoelectronic light detection device 35, e.g., the first conductivitytype III-V semiconductor material layer 35 a of the optoelectronic lightdetection device 35. Different than the embodiment that is depicted inFIG. 1, which includes an SOI substrate 5 and buried dielectric layer 3,in the embodiments formed on a bulk semiconductor substrate 2 a, asdepicted in FIG. 2, the vias 76 extend to an upper surface of the bulksemiconductor substrate 2 a adjacent to the portions of bulksemiconductor substrate 2 a that the first, second and thirdsemiconductor devices 10, 40, 80 are formed on. The seed surface of thebulk semiconductor substrate 2 a is separated from the portions of thebulk semiconductor substrate 2 a by an isolation dielectric material 19.

Still referring to FIG. 2, in some embodiments, the optical interconnect15, 25, 35 may be formed on a first interlevel dielectric layer 22 awithin the second level 75 of the electrical device, wherein the firstinterlevel dielectric layer 22 a is present overlying the thirdsemiconductor device 80. The first interlevel dielectric layer 22 a ofthe second level 75 may be formed over the metal lines 27 e that are inelectrical communication with the third semiconductor device 80. In someembodiments, the first interlevel dielectric layer 22 a of the secondlevel 75 does not extend over the first and second semiconductor devices10, 40. A second interlevel dielectric layer 24 may be present over thefirst semiconductor device 10, the second semiconductor device 40, andthe third semiconductor device 80, as well as being present over theoptical interconnect 15, 25, 35.

FIG. 3 depicts one embodiment of data transmission through theelectrical device that is depicted in FIGS. 1 and 2. The combination ofthe optoelectronic light emission device 15, the dielectric waveguide 15and the optoelectronic light detection device 35 provide an opticalinterconnect 15, 25, 35. In the embodiment depicted in FIG. 3, theoptoelectronic light emission device 15, the dielectric waveguide 25 andthe optoelectronic light detection device 35 provide an opticalinterconnect for data transmission between the first and secondsemiconductor devices 10, 40.

In one embodiment, data generated by the first semiconductor device 10in the first portion 20 of the SOI substrate 5 is transmitted byelectrical communication through the vias and interconnects 26 a, 26 c,27 a, 27 c to the optoelectronic light emission device 15. As usedherein, the term “electrical communication” means that a first structureor material can conduct electricity, i.e., is electrically conductive,to a second structure or material. Data transmission by electricalcommunication across the vias and interconnects 26 a, 26 c, 27 a, 27 cis depicted by arrows 201, 202, 203 in which the rate of datapropagation may range from a few Gb/s, e.g., 1 to 5 Gb/sec to ˜50Gb/sec, e.g., 1 Gb/sec to 25 Gb/sec. The data generated by the firstsemiconductor device 10 is converted into an optical signal by theoptoelectronic light emission device 15, which is typically a high-speedlaser. The arrow identified by reference number 204 illustrates theoptical transmission of the optical signal being emitted by theoptoelectronic light emission device 15 through the dielectric waveguide25 in the second portion 30 of the SOI substrate 5 to the optoelectroniclight detection device 35 in the third portion 45 of the SOI substrate5.

Optical transmission is faster than electrical communication. Forexample, optical transmission of the optical signal from theoptoelectronic light emission device 15 to the optoelectronic lightdetection device 35 through the dielectric waveguide 25 may be at a rateranging from 50 Gb/s (one wavelength channel) to ˜400 Gb/s (8 wavelengthchannel).

The optical signal is received by the optoelectronic light detectiondevice 35 that is present in the third portion 45 of the SOI substrate5, and is converted by the optoelectronic light detection device 35 froman optical signal to an electrical signal, which is typically ahigh-speed photodetector. The electrical signal is then transmitted byelectrical communication, as depicted by arrows 205, 206, 207, throughthe vias and interconnects 26 b, 26 d, 27 b, 27 d to the secondsemiconductor device 40 that is present in the third portion 45 of theSOI substrate 5. The rate of data propagation through the vias andinterconnects 26 b, 27 b may range from a few Gb/s, e.g., 1 to 5 Gb/s,to ˜50 Gb/s. For example, the rate of data propagation through the viasand interconnects 26 b, 27 b may range from 1 Gb/s to 25 Gb/s. It isnoted that the example depicted in FIG. 3 is provided for illustrativepurposes only, and is not intended to limit the present disclosuresolely thereto.

It is noted that the above structural and compositional examplesdescribed above with reference to FIGS. 1-3 are provided forillustrative purposes only, and are not intended to limit the presentdisclosure to only the above described examples. For example, theoperation of the electrical device has been described above withreference to the embodiment depicted in FIG. 1. The operation of theelectrical device is equally applicable to all the embodiments of thepresent disclosure, such as the embodiments consistent with FIG. 2. Thestructures and methods of the present disclosure, are now described inmore detail with reference to FIGS. 1 to 13.

FIG. 4 depicts one embodiment at least one semiconductor device 10, 40being formed on an SOI substrate 5 following back end of the line (BEOL)processing. The SOI substrate 5 includes an SOI layer 4, a burieddielectric layer 3, and base semiconductor substrate 2, as describedabove with reference to FIG. 1. The SOI substrate 5 may be formed by athermal bonding process, or alternatively, the SOI substrate 5 may beformed by an oxygen implantation process, which is referred to in theart as a separation by implantation of oxygen (SIMOX). In otherembodiments, deposition may be used to form the buried dielectric layer3 on a bulk semiconductor substrate 2. In this embodiment, the SOI layer4 may then be deposited on the buried dielectric layer 3 to provide theSOI substrate 5.

FIG. 4 depicts one embodiment of patterning the SOI substrate 5 toprovide islands of a remaining portion of the SOI layer 4 in the firstportion 20 of the SOI substrate 5 and the third portion 45 of the SOIsubstrate 5. These islands of remaining portions of the SOI layer 4 canprovide the site for the formation of the first and second semiconductordevices 10, 40.

Patterning the SOI substrate 5 may include deposition, photolithographyand etch processes. Specifically, in one example, a photoresist mask(not shown) is formed overlying the SOI layer 4 of the SOI substrate 5,in which the portion of the SOI layer 4 that is underlying thephotoresist mask provides the remaining portion of the SOI layer 4 thatis present in the first and third portions 20, 45 of the SOI substrate5. The exposed portions of the SOI layer 5, which are not protected bythe photoresist mask, are removed using a selective etch process. Toprovide the photoresist mask, a photoresist layer is first positioned onthe SOI layer 5. The photoresist layer may be provided by a blanketlayer of photoresist material that is formed utilizing a depositionprocess such as, for example, chemical vapor deposition, plasma enhancedchemical vapor deposition, evaporation or spin-on coating. The blanketlayer of photoresist material is then patterned to provide thephotoresist mask utilizing a lithographic process that may includeexposing the photoresist material to a pattern of radiation anddeveloping the exposed photoresist material utilizing a resistdeveloper.

Following the formation of the photoresist mask, a selective etchingprocess may remove the unprotected portions of the SOI layer 4. As usedherein, the term “selective” in reference to a material removal processdenotes that the rate of material removal for a first material isgreater than the rate of removal for at least another material of thestructure to which the material removal process is being applied. Forexample, in one embodiment, a selective etch may include an etchchemistry that removes a first material, i.e., SOI layer 4, selectivelyto a second material, i.e., buried dielectric layer 3, by a ratio of100:1 or greater.

For example, the transferring of the pattern provided by the photoresistinto the underlying structures may include an anisotropic etch. As usedherein, an “anisotropic etch process” denotes a material removal processin which the etch rate in the direction normal to the surface to beetched is greater than in the direction parallel to the surface to beetched. The anisotropic etch may include reactive-ion etching (RIE).Other examples of anisotropic etching that can be used at this point ofthe present disclosure include ion beam etching, plasma etching or laserablation.

FIG. 4 also depicts one embodiment of filling the portions of the SOIsubstrate 5 from which the SOI layer 4 was removed with an isolationdielectric material 19. The isolation dielectric material 19 may beformed using a deposition process. For example, the isolation dielectricmaterial 19 may be deposited using chemical vapor deposition (CVD).Variations of CVD processes include, but not limited to, AtmosphericPressure CVD (APCVD), Low Pressure CVD (LPCVD) and Plasma Enhanced CVD(EPCVD), Metal-Organic CVD (MOCVD) and combinations thereof may also beemployed. The isolation dielectric material 19 may also be depositedusing chemical solution deposition, spin or deposition, or in some casesmay be formed using thermal growth processes, such as thermal oxidation,nitridation or a combination thereof. Following deposition of theisolation dielectric material 19, the structure may be planarized usinga planarization process, such as chemical mechanical planarization(CMP).

FIG. 4 also depicts forming the first and second semiconductor devices10, 40 on the remaining portions of the SOI layer 4 in the first portion20 and the third portion 45 of the SOI substrate 5. In some embodiments,the first and second semiconductor devices 10, 40 may be composed ofFETS. One example of a process sequence for forming a FET deviceincludes depositing a layered stack including at least one gatedielectric material and at least on gate conductor material, andpatterning and etching the layered stack to provide a gate structure 13a, 13 b. At least one gate sidewall spacer 17 may then be formed on thesidewall of the gate structure 13 a, 13 b using deposition and etch backmethods. Source and drain regions 11 a, 11 b, 12 a, 12 b may be formedin the SOI layer 4 on opposing sides of the gate structures 13 a, 13 bby ion implantation of an n-type or p-type dopant. In some embodiments,raised source and drain regions structures may be formed. Block masks,e.g., photoresist block masks, may be employed to selectively processthe first and third portions 10, 45 of the SOI substrate 5 so that thefirst and second semiconductor devices 10, 40 may be devices of adifferent conductivity, e.g., n-type conductivity FET or p-typeconductivity FET. Following the formation of the first and secondsemiconductor devices 10, 40, the dielectric material 19 may be removedfrom the third portion 30 of the SOI substrate 5, in which the opticalinterconnect 15, 25, 35 is later formed. The dielectric material 19 maybe removed from the third portion 30 of the SOI substrate 5 usingdeposition, photolithography, and etch processing.

Still referring to FIG. 4, a first interlevel dielectric layer 21 may beblanket deposited covering the entirety of the SOI substrate 5 includingthe first and second semiconductor devices 10, 40. The first interleveldielectric layer 21 may be deposited using a chemical vapor depositionprocess, such as metal organic chemical vapor deposition, high densityplasma chemical vapor deposition, or plasma enhanced chemical vapordeposition. Following deposition of the first interlevel dielectriclayer 21, via openings may be formed through the interlevel dielectriclayer to the source region 11 a, 11 b, drain region 12 a, 12 b, and thegate structures 13 a, 13 b. The via openings may be formed usingphotolithography and etch processes. The via openings may be filled witha conductive material, such as a metal, to provide a first set ofelectrically conductive vias 26 a, 26 b. The conductive material may bedeposited using a physical vapor deposition (PVD) process, such asplating or sputtering. Electrically conductive lines 27 a, 27 b may thenbe formed on the first interlevel dielectric layer 21, and may be inelectrically communication with the first set of vias 26 a, 26 b. Theelectrically conductive lines 27 a, 27 b may be composed of anelectrically conductive material that is similar to the electricallyconductive material of the vias 26 a, 26 b. The electrically conductivelines 27 a, 27 b may be formed using physical vapor deposition andselective etch processing.

A second interlevel dielectric layer 22 may then be blanket depositedatop the first interlevel dielectric layer 21. A second set ofelectrically conductive vias 26 a, 26 b may then be formed through thesecond interlevel dielectric layer 22 and a second set of electricallyconductive lines 27 a, 27 b may be formed atop the second interleveldielectric layer 22. The second set of electrically conductive vias 26a, 26 b may be in electrical communication with the electricallyconductive lines 27 a, 27 b that are present on the first interleveldielectric layer 21. A third interlevel dielectric layer 23 may beformed atop the second interlevel dielectric layer 22.

Following formation of the third interlevel dielectric layer 23, vias 76may be formed through the first, second and third interlevel dielectriclayer 21, 22, 23, as well as the buried dielectric layer 3, to exposethe seed portion of the base semiconductor substrate 2. For example, thevia 76 may be formed using deposition, photolithography and etchprocesses similar to the above described process sequence for etchingthe SOI layer 4. More specifically, an etch mask, i.e., photoresistmask, is formed exposing the portion of the dielectric material layersthat are to be etched to expose the underlying surface of the basesemiconductor substrate 2 that provides the seed surface for epitaxialgrowth. Thereafter, an etch process etches the exposed portions of thefirst second and third dielectric layers 21, 22, 23, as well as theburied dielectric layer 3, selectively to at least the basesemiconductor substrate 2 and the etch mask. As used herein, the term“selective” in reference to a material removal process denotes that therate of material removal for a first material is greater than the rateof removal for at least another material of the structure to which thematerial removal process is being applied. For example, in oneembodiment, a selective etch may include an etch chemistry that removesa first material, i.e., buried dielectric layer 3, selectively to asecond material, i.e., base semiconductor substrate, by a ratio of 100:1or greater. The etch process may be an anisotropic etch process, such asreactive ion etch (RIE). Other anisotropic etch processes that aresuitable at this stage of the present disclosure include ion beametching, plasma etching or laser ablation. In some embodiments, at leastone via 76 is formed to adjacent to the first semiconductor device 10,and at least one via 76 is formed adjacent to the second semiconductordevice 40. In some embodiments, the first via 76 adjacent to the firstsemiconductor device 10 exposes a first seed surface of the basesemiconductor substrate 2 that provides for epitaxial growth for thebase layer, i.e., first conductivity type III-V semiconductor materiallayer 15 a of the optoelectronic light emission device 15, and thesecond via 76 adjacent to the second semiconductor device exposes asecond seed surface of the base semiconductor substrate 2 that providesfor epitaxial growth for the base layer, i.e., first conductivity typeIII-V semiconductor material layer 35 a of the optoelectronic lightdetection device 35.

FIG. 5 depicts one embodiment of epitaxially forming a III-Vsemiconductor material from the seed surface of SOI substrate 5, whereinthe III-V semiconductor material fills the vias 76, and provides atleast a base material layer for the optoelectronic light emission device15 and/or optoelectronic light detection device 35 for the opticalinterconnect. More specifically, FIG. 5 depicts epitaxially forming thefirst conductivity type III-V semiconductor material layer 15 a for theoptoelectronic light emission device 15 from the first seed surfacewithin the via 76 adjacent to the first semiconductor device 10, andepitaxially forming the first conductivity type III-V semiconductormaterial layer 35 a for the optoelectronic light detection device 35from the second seed surface within the via 76 adjacent to the secondsemiconductor device 40. The term “epitaxial material” denotes asemiconductor material that has been formed using an epitaxial growthand/or epitaxial deposition process. “Epitaxial growth and/or epitaxialdeposition” means the growth of a semiconductor material on a depositionsurface of a semiconductor material, in which the semiconductor materialbeing grown has substantially the same crystalline characteristics asthe semiconductor material of the deposition surface. In someembodiments, when the chemical reactants are controlled, and the systemparameters set correctly, the depositing atoms of an epitaxialdeposition process arrive at the deposition surface with sufficientenergy to move around on the surface and orient themselves to thecrystal arrangement of the atoms of the deposition surface. An epitaxialmaterial has substantially the same crystalline characteristics as thesemiconductor material of the deposition surface. For example, anepitaxial film deposited on a {100} crystal surface will take on a {100}orientation. The epitaxial deposition process may be carried out in thedeposition chamber of a chemical vapor deposition (CVD) apparatus.

A number of different sources may be used for the deposition ofepitaxial type III-V semiconductor material. In some embodiments, thesources for epitaxial growth of type III-V semiconductor materialinclude solid sources containing In, Ga, N, P elements and combinationsthereof and/or a gas precursor selected from the group consisting oftrimethylgallium (TMG), trimethylindium (TMI), tertiary-butylphosphine(TBP), phosphine (PH₃), ammonia (NH₃), and combinations thereof. Thetemperature for epitaxial deposition of type III-V semiconductormaterials typically ranges from 550° C. to 900° C. Although highertemperature typically results in faster deposition, the fasterdeposition may result in crystal defects and film cracking.

The first conductivity type III-V semiconductor material layer 15 a ofthe optoelectronic light emission device 15, and the first conductivitytype III-V semiconductor material layer 35 a of the optoelectronic lightdetection device 35, is typically doped to a first conductivity type.For example, the first conductivity III-V semiconductor material layers15 a, 35 a may be doped to an n-type conductivity. In other examples,the first conductivity type III-V semiconductor material layers 15 a, 35a may be doped to a p-type conductivity. The dopant may be introducedvia ion implantation or via in situ implantation. The effect of thedopant atom, i.e., whether it is a p-type or n-type dopant, depends uponthe site occupied by the dopant atom on the lattice of the basematerial. In a III-V semiconductor, atoms from group II act asacceptors, i.e., p-type, when occupying the site of a group III atom,while atoms in group VI act as donors, i.e., n-type, when they replaceatoms from group V. Dopant atoms from group IV, such a silicon (Si),have the property that they can act as acceptors or donor depending onwhether they occupy the site of group III or group V atoms respectively.Such impurities are known as amphoteric impurities.

It is noted that it is not necessary that the first conductivity typeIII-V semiconductor material layer 15 a for the optoelectronic lightemission device 15 and the first conductivity type III-V semiconductormaterial layer 35 a for the optoelectronic light detection device 35 beformed simultaneously, or have the same composition, or have the sameconductivity type. Block masks may be employed to independently processthe first conductivity type III-V semiconductor material layer 15 a forthe optoelectronic light emission device 15 and the first conductivitytype III-V semiconductor material layer 35 a for the optoelectroniclight detection device 35.

Following deposition, the first conductivity type III-V semiconductormaterial layers 15 a, 35 a are planarized. Planarization may includechemical mechanical planarization (CMP) or grinding.

The first conductivity type III-V semiconductor material layers 15 a, 35a are typically grown filling the vias 76, and extending over the uppersurface of the third interlevel dielectric layer 23. The firstconductivity type III-V semiconductor material layers 15 a, 35 a of theoptical interconnect are typically grown to a thickness ranging from 1micron to 2 microns, as measured from the upper surface of the thirdinterlevel dielectric layer 23. The portion of the first conductivitytype III-V semiconductor material layers 15 a, 35 a that are present inthe vias 76 may have a high defect density. For example, the defectdensity of the III-V semiconductor material within the vias 76 may rangefrom 10⁷ defects/cm³ to 10¹¹ defects/cm³. In another example, the defectdensity of the III-V semiconductor material within the vias 76 may rangefrom 10⁹ defects/cm³ to 10¹⁰ defects/cm³. The high defect density may becontained within the vias 76 in accordance with the principles of highaspect ratio defect trapping. More specifically, the high defect densityof the III-V semiconductor material layer having a high defect densitymay be contained within the vias 76 having an aspect ratio (i.e., heightto width ratio) being greater than 1:1, e.g., greater than 2:1.

The defect density within the first conductivity type III-Vsemiconductor material layers 15 a, 35 a reduces along the distance D3,D4 away from the via 76. For example, at a distance D3, D4 of 50 nm fromthe sidewall of the via 76, the defect density within the firstconductivity type III-V semiconductor material layers 15 a, 35 a may bereduced to 10⁶ defects/cm³. In another example, at a distance D3, D4 of50 nm from the sidewall of the via 76, the defect density within thefirst conductivity type III-V semiconductor material layers 15 a, 35 amay be reduced to 10⁶ defects/cm³. Typically, the farther away from thevia 27, the lower the defect density in the first conductivity typeIII-V semiconductor material layers 15 a, 35 a.

The portion of the first conductivity type III-V semiconductor materiallayers 15 a, 35 a that is present extending over the upper surface ofthe third interlevel dielectric layer 23 is typically etched to providethe base geometry of the optoelectronic light emission device 15 and theoptoelectronic light detection device 35. To provide the base geometryof the optoelectronic light emission device 15, and the optoelectroniclight detection device 35, the first conductivity type III-Vsemiconductor material layers 15 a, 35 a are typically etched usingphotolithography and selective etch processing to provide the width W3,W4 and length dimensions L2, L3 that are described above with referenceto FIG. 8.

FIG. 6 depicts one embodiment of forming an optoelectronic lightemission device 15 including the first conductivity type III-Vsemiconductor material layer 15 a, and forming an optoelectronic lightdetection device 35 including the first conductivity type III-Vsemiconductor material layer 35 a. In some embodiments, followingformation of the first conductivity type III-V semiconductor materiallayer 15 a of the optoelectronic light emission device 15, the materiallayers of the III-V multiple quantum well layered stack 15 b may beepitaxially formed on the first conductivity type III-V semiconductormaterial layer 15 a, which may provide the base layer of theoptoelectronic light emission device 15. The III-V multiple quantum welllayered stack 15 b is typically a layered stack of intrinsicsemiconductor materials. Each material layer of the III-V multiplequantum well layered stack 15 b can be formed using an epitaxialdeposition process, which may be carried out in the deposition chamberof a CVD apparatus. The epitaxial deposition process for forming theIII-V multiple quantum well layered stack 15 b may be a selectiveepitaxial deposition process. The fact that the process is selectivemeans that the III-V semiconductor material only on forms on the exposedsemiconductor surfaces, such as the upper surface of the firstconductivity type III-V semiconductor material layer 15 a of theoptoelectronic light emission device, and is not formed on dielectricsurfaces, such as the uppermost third interlevel dielectric layer 23.The different compositions of the III-V multiple quantum well layeredstack 15 b may be provided by changing and cycling the precursor gassesused in depositing the different compositions of the III-V compoundsemiconductor materials for the different layers within the III-Vmultiple quantum well layered stack 15 b.

In some embodiments, the intrinsic III-V semiconductor material layer 35b of the optoelectronic light detection device 35 may be epitaxiallyformed concurrently with the III-V multiple quantum well layered stack15 b of the optoelectronic light emission device 15. In this embodiment,the intrinsic III-V semiconductor material layer 35 b has the samecomposition as the III-V multiple quantum well layered stack 15 b. Inother embodiments, the intrinsic III-V semiconductor material layer 35 bof the optoelectronic light detecting device 35 is epitaxially formedseparately from the III-V multiple quantum well layered stack 15 b ofthe optoelectronic light emission device 15 by employing block masks toindependently epitaxially deposit III-V semiconductor material layersfor the optoelectronic light emission device 15 and the optoelectroniclight detection device 35.

Following the formation of the III-V multiple quantum well layered stack15 b of the optoelectronic light emission device 15 and/or the intrinsicIII-V semiconductor material layer 35 b of the optoelectronic lightdetection device 35, at least one of the second conductivity type III-Vsemiconductor material layer 15 c of the optoelectronic light emissiondevice 15 and the second conductivity type III-V semiconductor materiallayer 35 c of the optoelectronic light detection device 35 may beepitaxially formed. The second conductivity type III-V semiconductormaterial layer 15 c is formed epitaxially on an upper surface of theIII-V multiple quantum well layered stack 15 b of the optoelectroniclight emission device 15. The second conductivity III-V semiconductormaterial layer 35 c is epitaxially formed on an upper surface of theintrinsic III-V semiconductor material layer 35 b of the optoelectroniclight emission device 35.

Each of the second conductivity type III-V semiconductor material layer15 c that is epitaxially formed on the III-V multiple quantum welllayered stack 15 b, and the second conductivity type III-V semiconductormaterial layer 35 c that is epitaxially formed on the intrinsic III-Vsemiconductor material layer 35 b, may have a conductivity type that isopposite the conductivity type of the first conductivity type III-Vsemiconductor material layer 15 a and the first conductivity type III-Vsemiconductor material layer 35 a, respectively. For example, when thefirst conductivity type III-V semiconductor material layer 15 a has ann-type conductivity, the second conductivity type III-V semiconductormaterial layer 15 c has a p-type conductivity.

Each of the second conductivity type III-V semiconductor material layer15 c that is epitaxially formed on the III-V multiple quantum welllayered stack 15 b, and the second conductivity type III-V semiconductormaterial layer 35 c that is epitaxially formed on the intrinsic III-Vsemiconductor material layer 35 b, may be formed using an epitaxialdeposition process that is similar to the process described above forforming the first conductivity III-V semiconductor material layer 15 aand the first conductivity III-V semiconductor material layer 35 a. Thedopant of the second conductivity type III-V semiconductor materiallayer 15 c and/or second conductivity type III-V semiconductor materiallayer 35 c may be introduced in-situ or may be introduced to the III-Vsemiconductor material by ion implantation.

In one embodiment, the second conductivity type III-V semiconductormaterial layer 15 c and the second conductivity type III-V semiconductormaterial layer 35 c have the same composition. In other embodiments, thesecond conductivity type III-V semiconductor material layer 35 c of theoptoelectronic light detection device 35 is epitaxially formedseparately from the second conductivity type III-V material layer 15 cof the optoelectronic light emission device 15 by employing block masks.Following formation of the second conductivity type III-V semiconductormaterial layer 15 c of the optoelectronic light emission device 15and/or second conductivity type III-V semiconductor material layer 35 cof the optoelectronic light detection device 35, the height H1 of thematerials stacks for the optoelectronic light emission device 15 and theoptoelectronic light detection device 35 may range from 500 nm to 5000nm, as measured from the upper surface of the third interleveldielectric layer 23.

FIG. 7 depicts one embodiment of forming a dielectric waveguide 25 onthe third interlevel dielectric layer 23 between the optoelectroniclight emission device 15 and the optoelectronic light detection device35. In some embodiments, the dielectric material for the dielectricwaveguide 25 may be deposited on the structure depicted in FIG. 6 usingchemical vapor deposition (CVD). Variations of CVD processes include,but not limited to, Atmospheric Pressure CVD (APCVD), Low Pressure CVD(LPCVD) and Plasma Enhanced CVD (EPCVD), Metal-Organic CVD (MOCVD) andcombinations thereof may also be employed. The dielectric material mayalso be deposited using chemical solution deposition, spin ordeposition, or in some cases may be formed using thermal growthprocesses, such as thermal oxidation, nitridation or a combinationthereof.

The dielectric material may then be patterned and etched to provide adielectric waveguide 25 having the geometry depicted in FIG. 8.Patterning the dielectric material may include deposition,photolithography and etch processes. Specifically, in one example, aphotoresist mask (not shown) is formed overlying the dielectricmaterial, in which the portion of the dielectric material that isunderlying the photoresist mask provides the dielectric waveguide 25.The exposed portions of the dielectric material, which are not protectedby the photoresist mask, are removed using a selective etch process.Following the formation of the photoresist mask, an etching process mayremove the unprotected portions of the dielectric material. For example,the transferring of the pattern provided by the photoresist into theunderlying structures may include an anisotropic etch. The anisotropicetch may include reactive-ion etching (RIE). Other examples ofanisotropic etching that can be used at this point of the presentdisclosure include ion beam etching, plasma etching or laser ablation.

Referring to FIG. 1, in a following process step, contacts 60 a, 60 b,65 a, 65 b are formed to the optoelectronic light emission device 15 andthe optoelectronic light detection device 35. In some embodiments, afirst contact 60 a, 60 b may be formed to each of the first conductivitytype III-V semiconductor material layer 15 a of the optoelectronic lightemission device 15, and the first conductivity type III-V semiconductormaterial layer 35 a of the optoelectronic light detection device 35. Insome embodiments, a second contact 65 a, 65 b may be formed to each ofthe second conductivity III-V semiconductor material layer 15 c of theoptoelectronic light emission device 15, and the second conductivityIII-V semiconductor material layer 35 c of the optoelectronic lightdetection device 35.

Forming the contacts 60 a, 60 b, 65 a, 65 b may begin with patterningthe second conductivity type III-V semiconductor material layers 15 c,35 c, the III-V multiple quantum well layered stack 15 b and theintrinsic III-V semiconductor material layer 35 b to expose a portion ofthe each of the first conductivity type III-V semiconductor materiallayer 15 a of the optoelectronic light emission device 15 and the firstconductivity type III-V semiconductor material layer 35 a of theoptoelectronic light detection device 35. Patterning the layeredmaterial stacks for the optoelectronic light emission device 15 and theoptoelectronic light detection device 35 may include photolithographyand etch processes.

The contacts 60 a, 60 b, 65 a, 65 b may be composed of a metal, whichcan be deposited using a physical vapor deposition (PVD) method, such asa sputtering or plating. The material layer for the contacts 60 a, 60 b,65 a, 65 b may be deposited as a single blanket deposited layer.Following deposition, the material layer for the contacts 60 a, 60 b, 65a, 65 b may be patterned and etched so that remaining portions arepresent in direct contact with the first and second conductivity typeIII-V material layers 15 a, 35 a, 15 c, 35 c of the optoelectronic lightemission device 15 and the optoelectronic light detection device 35.

In some embodiments, following the formation of the contacts 60 a, 60 b,65 a, 65 b, a fourth interlevel dielectric layer 24 may be formed overthe structure including the optoelectronic light emission device 15, theoptoelectronic light detection device 35, and the dielectric wave guide25. The fourth interlevel dielectric layer 24 may be formed by chemicalvapor deposition (CVD), spin on coating, solution deposition or otherdeposition methods.

In some embodiments, interconnect wiring, i.e., vias 26 c and lines 27c, may be formed to provide electrical communication between the firstsemiconductor device 10 and the optoelectronic light emission device 15.Interconnect wiring, i.e., vias 26 d and lines 27 d, may also be formedto provide electrical communication between the second semiconductordevice 40 and the optoelectronic light detection device 35. The fourthinterlevel dielectric 24 and the third interlevel dielectric 23 on thefirst and third portions 10, 45 of the SOI substrate 5 may be patternedand etched to form via holes to the various contacts 60 a, 60 b, 65 a,65 b of the optoelectronic light emission device 15 and theoptoelectronic light detection device 35, as well as to the lines 27 a,27 b that are in electrical communication with the first and secondsemiconductor devices 10, 40. Following via formation, interconnects 27c, 27 d are formed by depositing a conductive metal into the via holesusing deposition methods, such as CVD, sputtering or plating. A firstline 27 c may then be formed to provide electrical communication betweenthe vias 26 c to the first semiconductor device 10 and the vias 26 c tothe optoelectronic light emission device 15. A second line 27 d may thenbe formed to provide electrical communication between the vias 26 d tothe second semiconductor device 40 and the vias 26 d to theoptoelectronic light detection device 35.

FIG. 9 depicts semiconductor devices 10, 40, 90 that have been formed ona bulk semiconductor substrate 2 a following back end of the line (BEOL)processing, wherein vias 76 have been formed through interleveldielectric layers 21 a to expose a seed surface of the bulk substrate 2a. In this embodiment, three semiconductor devices 10, 40, 80 are formedon the upper surface of a bulk semiconductor substrate 2 a. Isolationbetween adjacent semiconductor devices 10, 40, 80 is provided by shallowtrench isolation (STI) regions provided by an isolation dielectricmaterial 19. Seed surfaces for epitaxial growth are present between theportions of the bulk substrate 2 a that are occupied by thesemiconductor devices 10, 40, 80. The process steps that provide thesemiconductor devices 10, 40, 80 and isolation dielectric material 19that is depicted in FIG. 9 is similar to the process steps that providethe semiconductor devices 10, 40, 80 and isolation dielectric material19 that are described above with reference to FIG. 4. Following theformation of the semiconductor devices 10, 40, 80, a first interleveldielectric layer 21 a is formed over the bulk semiconductor substrate 2a and the semiconductor devices 10, 40, 80. Vias 26 a, 26 b, 26 e arethen formed to the semiconductor devices 10, 40, 80. Metal lines 27 emay then be formed to provide electrical communication to the thirdsemiconductor device 80.

FIG. 10 depicts forming a second interlevel dielectric layer 22 aoverlying the structure depicted in FIG. 9, and patterning theinterlevel dielectric layers 21 a, 22 a to provide vias 76 extendingthrough the interlevel dielectric layers 21 to expose seed surfaceportions of the bulk semiconductor substrate 2 a. The process sequencefor forming the vias 76 depicted in FIG. 10 is similar to the processsequence that has been described above for forming the vias 76 depictedin FIG. 4.

FIG. 11 depicts epitaxially forming an optoelectronic light emissiondevice 15, and an optoelectronic light detection device 35, wherein atleast one material layer of at least one of the optoelectronic lightemission device 15 and the optoelectronic light detection device 35 isepitaxially grown from the seed substrate surface through at least onevia 76 extending onto the upper surface of the second interleveldielectric layer 22 a. The process sequence for forming the III-V lightemission device 15 and the III-V light detection device 35 that isdepicted in FIG. 11 is similar to the process sequence that is used toform the III-V light emission device 15 and the III-V light detectiondevice 35 that has been described above with reference to FIGS. 5 and 6.

FIG. 12 depicting forming the dielectric material 25′ for the dielectricwaveguide on the structure depicted in FIG. 11. The dielectric material25′ is blanket deposited and then planarized so that the upper surfaceof the dielectric material 25′ is coplanar with the upper surface of theIII-V light emission device 15 and the III-V light detection device 35.

FIG. 13 depicting pattering the dielectric material layer 25′ depictedin FIG. 12 to provide a dielectric wave guide 25. The dielectric waveguide 25 may have a tapered geometry, as described with reference toFIG. 8. The process for patterning the dielectric waveguide 25 from thedielectric material layer 25′ has been described above with reference toFIGS. 7 and 8.

Following pattering of the dielectric waveguide 25, the secondinterlevel dielectric layer 22 may be etched to remove the portions thatare extending over the first and second semiconductor devices 10, 40.Contacts 65 a, 65 e may then be formed to the III-V light emissiondevice 15 and the III-V light detection device 35. For the purposes ofclarity the back contact to III-V light emission device 15 and the III-Vlight detection device 35 are not depicted in FIG. 13. The contactscheme for the structure depicted in FIG. 13 may be similar to thecontact scheme that is depicted in FIG. 1. Further, metal lines 27 a, 27b may be formed in electrical communication with the vias 26 a, 26 b tothe first and second semiconductor devices 10, 40.

Referring to FIG. 2, an interlevel dielectric layer 24 may then beblanket deposited on the structure depicted in FIG. 13 that covers theIII-V light emission device 15, the dielectric waveguide 25 and theIII-V light detection device 35. Metal lines and vias 26 a, 26 d, 27 c,27 d may then be formed providing electrical communication between theIII-V light emission device 15, and the first semiconductor device 10,and electrical communication between the III-V light detection device 35and the second semiconductor device 40.

Methods as described herein may be used in the fabrication of integratedcircuit chips. The resulting integrated circuit chips can be distributedby the fabricator in raw wafer form (that is, as a single wafer that hasmultiple unpackaged chips), as a bare die, or in a packaged form. In thelatter case the chip is mounted in a single chip package (such as aplastic carrier, with leads that are affixed to a motherboard or otherhigher level carrier) or in a multichip package (such as a ceramiccarrier that has either or both surface interconnections or buriedinterconnections). In any case the chip is then integrated with otherchips, discrete circuit elements, and/or other signal processing devicesas part of either (a) an intermediate product, such as a motherboard, or(b) an end product. The end product can be any product that includesintegrated circuit chips, ranging from toys and other low-endapplications to advanced computer products having a display, a keyboardor other input device, and a central processor.

While the methods and structures of the present disclosure have beenparticularly shown and described with respect to preferred embodimentsthereof, it will be understood by those skilled in the art that theforegoing and other changes in forms and details may be made withoutdeparting from the spirit and scope of the present disclosure. It istherefore intended that the present disclosure not be limited to theexact forms and details described and illustrated, but fall within thescope of the appended claims.

What is claimed is:
 1. An electrical device comprising: an opticalinterconnect positioned on a portion of the semiconductor substrate thatis positioned between portions of a semiconductor substrate includingelectrical components, the optical interconnect is present on at leastone interlevel dielectric layer that is present over at least one of theelectrical components, the optical interconnect including a III-V lightemission device and a III-V light detection device, wherein at least onematerial layer of the optical interconnect is an epitaxial material thatis in direct contact with a semiconductor material layer of thesubstrate that is overlying a dielectric layer.
 2. The electrical deviceof claim 1, wherein the semiconductor substrate is an SOI substrate. 3.The electronic device of claim 1 further comprising a dielectricwaveguide positioned between the III-V light emission device and theIII-V light detection device.
 4. The electronic device of claim 1,wherein the electronic components comprises a switching device selectedfrom the group consisting of field effect transistor (FET), fin fieldeffect transistor (FinFET), metal oxide semiconductor field effecttransistor (MOSFET), bipolar junction transistor (BJT), Schottky barriersemiconductor device, junction field effect transistor (JFET) andcombinations thereof, or the first electronic component comprises amemory device selected from the group consisting of flash memory,dynamic random access memory, embedded dynamic random access memory, andcombinations thereof.
 5. The electronic device of claim 1, wherein theIII-V light emission device is a quantum well laser comprising a firstconductivity type III-V semiconductor material layer, a quantum wellstack of III-V semiconductor material layers that is present on thefirst conductivity type III-V semiconductor material layer, and a secondconductivity type III-V semiconductor material layer that is present onthe quantum well stack of III-V semiconductor material layers.
 6. Theelectronic device of claim 1, wherein the III-V light detection deviceincludes a first conductivity type III-V semiconductor material layer,an intrinsic III-V semiconductor material layer, and a secondconductivity type III-V semiconductor material layer.
 7. The electronicdevice of claim 1, wherein the first electronic component is inelectrical communication through at least one first interconnect to theIII-V light emission device of the optical interconnect, and the secondelectronic component is in electrical communication through at least onesecond interconnect to the III-V light detection device of the opticalinterconnect.
 8. The electrical device of claim 2, wherein thedielectric waveguide has a width that tapers from a first face having afirst width that is adjacent to the III-V light emission device to asecond face having a second width that is adjacent to the III-V lightdetection device.
 9. The electrical device of claim 8, wherein thedielectric waveguide is comprised of a dielectric material selected fromthe group consisting of amorphous silicon, polysilicon, poly III-Vsemiconductor material, aluminum nitride (AlN) and a combinationthereof.
 10. An electrical device comprising: an optical interconnectpositioned on the interlevel dielectric and in communication with asemiconductor device, the optical interconnect including, an epitaxialmaterial that is in direct contact with a seed surface of an underlyingsemiconductor surface through a via extending through the interleveldielectric layer.
 11. The electrical device of claim 10, wherein theoptical interconnect includes a III-V light emitting device, adielectric waveguide and a III-V light detecting device.
 12. Theelectrical device of claim 10, wherein the semiconductor devicecomprises a first switching device selected from the group consisting offield effect transistor (FET), fin field effect transistor (FinFET),metal oxide semiconductor field effect transistor (MOSFET), bipolarjunction transistor (BJT), Schottky barrier semiconductor device,junction field effect transistor (JFET) and combinations thereof, or thesemiconductor device comprises a first memory device selected from thegroup consisting of flash memory, dynamic random access memory, embeddeddynamic random access memory and combinations thereof.
 13. Theelectrical device of claim 11, wherein the optoelectronic light emissiondevice is a quantum well laser comprising a first conductivity typeIII-V semiconductor material layer, a quantum well stack of III-Vsemiconductor material layers that is present on the first conductivitytype III-V semiconductor material layer, and a second conductivity typeIII-V semiconductor material layer that is present on the quantum wellstack of III-V semiconductor material layers.
 14. The electrical deviceof claim 11, wherein the optoelectronic light detector device comprisesa first conductivity type III-V semiconductor layer, an intrinsic III-Vsemiconductor material layer, and a second conductivity type III-Vsemiconductor material layer.
 15. A method of forming an electricaldevice comprising: forming a plurality electrical components; andforming an optical interconnect on a surface of the at least oneinterlevel dielectric layer overlying and between at least two adjacentelectrical components of said plurality of electrical components,wherein at least one material layer of the optical interconnect isepitaxial grown from a seed surface through at least one via extendingonto the upper surface of the at least one interlevel dielectric layer.16. The method of claim 15 further comprising depositing at least oneinterlevel dielectric layer over the first, second and third portions ofthe substrate.
 17. The method of claim 16 further comprising etching atleast one via through the at least one interlevel dielectric layer toexpose the seed substrate surface in the second portion of thesubstrate.
 18. The method of claim 15, wherein the optical interconnectincludes a III-V light emitting device, a dielectric waveguide and aIII-V light detecting device.
 19. The method of claim 15, wherein atleast one of the III-V light emitting device and the III-V lightdetecting device is a quantum well laser comprising a first conductivitytype III-V semiconductor material layer, a quantum well stack of III-Vsemiconductor material layers that is present on the first conductivitytype III-V semiconductor material layer, and a second conductivity typeIII-V semiconductor material layer that is present on the quantum wellstack of III-V semiconductor material layers.
 20. The method of claim15, wherein at least one of the III-V light emitting device and theIII-V light detecting device comprises a first conductivity type III-Vsemiconductor layer, an intrinsic III-V semiconductor material layer,and a second conductivity type III-V semiconductor material layer.